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                                <h1 id="autorun"><a name="autorun" class="plugin-anchor" href="#autorun"><i class="fa fa-link" aria-hidden="true"></i></a>Autorun</h1>
<details>
    <summary style="color: white; background:green;padding:5px;margin:5px;border-radius:2px">egghead.io &#x7B2C;9&#x8BFE;: &#x81EA;&#x5B9A;&#x4E49;&#x53CD;&#x5E94;</summary>
    <br>
    <div style="padding:5px;">
        <iframe style="border: none;" width="760" height="427" src="https://egghead.io/lessons/react-write-custom-mobx-reactions-with-when-and-autorun/embed">
    </iframe></div>
    <a style="font-style:italic;padding:5px;margin:5px;" href="https://egghead.io/lessons/react-write-custom-mobx-reactions-with-when-and-autorun" target="_blank">&#x5728; egghead.io &#x4E0A;&#x89C2;&#x770B;</a>
</details>

<p>&#x5F53;&#x4F60;&#x60F3;&#x521B;&#x5EFA;&#x4E00;&#x4E2A;&#x54CD;&#x5E94;&#x5F0F;&#x51FD;&#x6570;&#xFF0C;&#x800C;&#x8BE5;&#x51FD;&#x6570;&#x672C;&#x8EAB;&#x6C38;&#x8FDC;&#x4E0D;&#x4F1A;&#x6709;&#x89C2;&#x5BDF;&#x8005;&#x65F6;,&#x53EF;&#x4EE5;&#x4F7F;&#x7528; <code>mobx.autorun</code>&#x3002;
&#x8FD9;&#x901A;&#x5E38;&#x662F;&#x5F53;&#x4F60;&#x9700;&#x8981;&#x4ECE;&#x53CD;&#x5E94;&#x5F0F;&#x4EE3;&#x7801;&#x6865;&#x63A5;&#x5230;&#x547D;&#x4EE4;&#x5F0F;&#x4EE3;&#x7801;&#x7684;&#x60C5;&#x51B5;&#xFF0C;&#x4F8B;&#x5982;&#x6253;&#x5370;&#x65E5;&#x5FD7;&#x3001;&#x6301;&#x4E45;&#x5316;&#x6216;&#x8005;&#x66F4;&#x65B0;UI&#x7684;&#x4EE3;&#x7801;&#x3002;
&#x5F53;&#x4F7F;&#x7528; <code>autorun</code> &#x65F6;&#xFF0C;&#x6240;&#x63D0;&#x4F9B;&#x7684;&#x51FD;&#x6570;&#x603B;&#x662F;&#x7ACB;&#x5373;&#x88AB;&#x89E6;&#x53D1;&#x4E00;&#x6B21;&#xFF0C;&#x7136;&#x540E;&#x6BCF;&#x6B21;&#x5B83;&#x7684;&#x4F9D;&#x8D56;&#x5173;&#x7CFB;&#x6539;&#x53D8;&#x65F6;&#x4F1A;&#x518D;&#x6B21;&#x88AB;&#x89E6;&#x53D1;&#x3002;
&#x76F8;&#x6BD4;&#x4E4B;&#x4E0B;&#xFF0C;<code>computed(function)</code> &#x521B;&#x5EFA;&#x7684;&#x51FD;&#x6570;&#x53EA;&#x6709;&#x5F53;&#x5B83;&#x6709;&#x81EA;&#x5DF1;&#x7684;&#x89C2;&#x5BDF;&#x8005;&#x65F6;&#x624D;&#x4F1A;&#x91CD;&#x65B0;&#x8BA1;&#x7B97;&#xFF0C;&#x5426;&#x5219;&#x5B83;&#x7684;&#x503C;&#x4F1A;&#x88AB;&#x8BA4;&#x4E3A;&#x662F;&#x4E0D;&#x76F8;&#x5173;&#x7684;&#x3002;
&#x7ECF;&#x9A8C;&#x6CD5;&#x5219;&#xFF1A;&#x5982;&#x679C;&#x4F60;&#x6709;&#x4E00;&#x4E2A;&#x51FD;&#x6570;&#x5E94;&#x8BE5;&#x81EA;&#x52A8;&#x8FD0;&#x884C;&#xFF0C;&#x4F46;&#x4E0D;&#x4F1A;&#x4EA7;&#x751F;&#x4E00;&#x4E2A;&#x65B0;&#x7684;&#x503C;&#xFF0C;&#x8BF7;&#x4F7F;&#x7528;<code>autorun</code>&#x3002;
&#x5176;&#x4F59;&#x60C5;&#x51B5;&#x90FD;&#x5E94;&#x8BE5;&#x4F7F;&#x7528; <code>computed</code>&#x3002; Autoruns &#x662F;&#x5173;&#x4E8E; <em>&#x542F;&#x52A8;&#x6548;&#x679C;</em> (initiating effects) &#x7684; &#xFF0C;&#x800C;&#x4E0D;&#x662F;&#x4EA7;&#x751F;&#x65B0;&#x7684;&#x503C;&#x3002;
&#x5982;&#x679C;&#x5B57;&#x7B26;&#x4E32;&#x4F5C;&#x4E3A;&#x7B2C;&#x4E00;&#x4E2A;&#x53C2;&#x6570;&#x4F20;&#x9012;&#x7ED9; <code>autorun</code> &#xFF0C;&#x5B83;&#x5C06;&#x88AB;&#x7528;&#x4F5C;&#x8C03;&#x8BD5;&#x540D;&#x3002;</p>
<p>&#x4F20;&#x9012;&#x7ED9; autorun &#x7684;&#x51FD;&#x6570;&#x5728;&#x8C03;&#x7528;&#x540E;&#x5C06;&#x63A5;&#x6536;&#x4E00;&#x4E2A;&#x53C2;&#x6570;&#xFF0C;&#x5373;&#x5F53;&#x524D; reaction(autorun)&#xFF0C;&#x53EF;&#x7528;&#x4E8E;&#x5728;&#x6267;&#x884C;&#x671F;&#x95F4;&#x6E05;&#x7406; autorun&#x3002;</p>
<p>&#x5C31;&#x50CF; <a href="%20observer-component.md"><code>@ observer</code> &#x88C5;&#x9970;&#x5668;/&#x51FD;&#x6570;</a>&#xFF0C;<code>autorun</code> &#x53EA;&#x4F1A;&#x89C2;&#x5BDF;&#x5728;&#x6267;&#x884C;&#x63D0;&#x4F9B;&#x7684;&#x51FD;&#x6570;&#x65F6;&#x6240;&#x4F7F;&#x7528;&#x7684;&#x6570;&#x636E;&#x3002;</p>
<pre><code class="lang-javascript"><span class="hljs-keyword">var</span> numbers = observable([<span class="hljs-number">1</span>,<span class="hljs-number">2</span>,<span class="hljs-number">3</span>]);
<span class="hljs-keyword">var</span> sum = computed(() =&gt; numbers.reduce((a, b) =&gt; a + b, <span class="hljs-number">0</span>));

<span class="hljs-keyword">var</span> disposer = autorun(() =&gt; <span class="hljs-built_in">console</span>.log(sum.get()));
<span class="hljs-comment">// &#x8F93;&#x51FA; &apos;6&apos;</span>
numbers.push(<span class="hljs-number">4</span>);
<span class="hljs-comment">// &#x8F93;&#x51FA; &apos;10&apos;</span>

disposer();
numbers.push(<span class="hljs-number">5</span>);
<span class="hljs-comment">// &#x4E0D;&#x4F1A;&#x518D;&#x8F93;&#x51FA;&#x4EFB;&#x4F55;&#x503C;&#x3002;`sum` &#x4E0D;&#x4F1A;&#x518D;&#x91CD;&#x65B0;&#x8BA1;&#x7B97;&#x3002;</span>
</code></pre>
<h2 id="&#x9009;&#x9879;"><a name="&#x9009;&#x9879;" class="plugin-anchor" href="#&#x9009;&#x9879;"><i class="fa fa-link" aria-hidden="true"></i></a>&#x9009;&#x9879;</h2>
<p>Autorun &#x63A5;&#x6536;&#x7B2C;&#x4E8C;&#x4E2A;&#x53C2;&#x6570;&#xFF0C;&#x5B83;&#x662F;&#x4E00;&#x4E2A;&#x53C2;&#x6570;&#x5BF9;&#x8C61;&#xFF0C;&#x6709;&#x5982;&#x4E0B;&#x53EF;&#x9009;&#x7684;&#x53C2;&#x6570;:</p>
<ul>
<li><code>delay</code>: &#x53EF;&#x7528;&#x4E8E;&#x5BF9;&#x6548;&#x679C;&#x51FD;&#x6570;&#x8FDB;&#x884C;&#x53BB;&#x6296;&#x52A8;&#x7684;&#x6570;&#x5B57;(&#x4EE5;&#x6BEB;&#x79D2;&#x4E3A;&#x5355;&#x4F4D;)&#x3002;&#x5982;&#x679C;&#x662F; 0(&#x9ED8;&#x8BA4;&#x503C;) &#x7684;&#x8BDD;&#xFF0C;&#x90A3;&#x4E48;&#x4E0D;&#x4F1A;&#x8FDB;&#x884C;&#x53BB;&#x6296;&#x3002;</li>
<li><code>name</code>: &#x5B57;&#x7B26;&#x4E32;&#xFF0C;&#x7528;&#x4E8E;&#x5728;&#x4F8B;&#x5982;&#x50CF; <a href="spy.html"><code>spy</code></a> &#x8FD9;&#x6837;&#x4E8B;&#x4EF6;&#x4E2D;&#x7528;&#x4F5C;&#x6B64; reaction &#x7684;&#x540D;&#x79F0;&#x3002;</li>
<li><code>onError</code>: &#x7528;&#x6765;&#x5904;&#x7406; reaction &#x7684;&#x9519;&#x8BEF;&#xFF0C;&#x800C;&#x4E0D;&#x662F;&#x4F20;&#x64AD;&#x5B83;&#x4EEC;&#x3002;</li>
<li><code>scheduler</code>: &#x8BBE;&#x7F6E;&#x81EA;&#x5B9A;&#x4E49;&#x8C03;&#x5EA6;&#x5668;&#x4EE5;&#x51B3;&#x5B9A;&#x5982;&#x4F55;&#x8C03;&#x5EA6; autorun &#x51FD;&#x6570;&#x7684;&#x91CD;&#x65B0;&#x8FD0;&#x884C;</li>
</ul>
<h2 id="delay-&#x9009;&#x9879;"><a name="delay-&#x9009;&#x9879;" class="plugin-anchor" href="#delay-&#x9009;&#x9879;"><i class="fa fa-link" aria-hidden="true"></i></a><code>delay</code> &#x9009;&#x9879;</h2>
<pre><code class="lang-javascript">autorun(() =&gt; {
    <span class="hljs-comment">// &#x5047;&#x8BBE; profile.asJson &#x8FD4;&#x56DE;&#x7684;&#x662F; observable Json &#x8868;&#x793A;&#xFF0C;</span>
    <span class="hljs-comment">// &#x6BCF;&#x6B21;&#x53D8;&#x5316;&#x65F6;&#x5C06;&#x5176;&#x53D1;&#x9001;&#x7ED9;&#x670D;&#x52A1;&#x5668;&#xFF0C;&#x4F46;&#x53D1;&#x9001;&#x524D;&#x81F3;&#x5C11;&#x8981;&#x7B49;300&#x6BEB;&#x79D2;&#x3002;</span>
    <span class="hljs-comment">// &#x5F53;&#x53D1;&#x9001;&#x540E;&#xFF0C;profile.asJson &#x7684;&#x6700;&#x65B0;&#x503C;&#x4F1A;&#x88AB;&#x4F7F;&#x7528;&#x3002;</span>
    sendProfileToServer(profile.asJson);
}, { delay: <span class="hljs-number">300</span> });
</code></pre>
<h2 id="onerror-&#x9009;&#x9879;"><a name="onerror-&#x9009;&#x9879;" class="plugin-anchor" href="#onerror-&#x9009;&#x9879;"><i class="fa fa-link" aria-hidden="true"></i></a><code>onError</code> &#x9009;&#x9879;</h2>
<p>&#x5728; autorun &#x548C;&#x6240;&#x6709;&#x5176;&#x4ED6;&#x7C7B;&#x578B; reaction &#x4E2D;&#x629B;&#x51FA;&#x7684;&#x5F02;&#x5E38;&#x4F1A;&#x88AB;&#x6355;&#x83B7;&#x5E76;&#x6253;&#x5370;&#x5230;&#x63A7;&#x5236;&#x53F0;&#xFF0C;&#x4F46;&#x4E0D;&#x4F1A;&#x5C06;&#x5F02;&#x5E38;&#x4F20;&#x64AD;&#x56DE;&#x539F;&#x59CB;&#x5BFC;&#x81F4;&#x5F02;&#x5E38;&#x7684;&#x4EE3;&#x7801;&#x3002;
&#x8FD9;&#x662F;&#x4E3A;&#x4E86;&#x786E;&#x4FDD;&#x4E00;&#x4E2A;&#x5F02;&#x5E38;&#x4E2D;&#x7684; reaction &#x4E0D;&#x4F1A;&#x963B;&#x6B62;&#x5176;&#x4ED6;&#x53EF;&#x80FD;&#x4E0D;&#x76F8;&#x5173;&#x7684; reaction &#x7684;&#x9884;&#x5B9A;&#x6267;&#x884C;&#x3002;
&#x8FD9;&#x4E5F;&#x5141;&#x8BB8; reaction &#x4ECE;&#x5F02;&#x5E38;&#x4E2D;&#x6062;&#x590D;; &#x629B;&#x51FA;&#x5F02;&#x5E38;&#x4E0D;&#x4F1A;&#x7834;&#x574F; MobX&#x7684;&#x8DDF;&#x8E2A;&#xFF0C;&#x56E0;&#x6B64;&#x5982;&#x679C;&#x9664;&#x53BB;&#x5F02;&#x5E38;&#x7684;&#x539F;&#x56E0;&#xFF0C;reaction &#x7684;&#x540E;&#x7EED;&#x8FD0;&#x884C;&#x53EF;&#x80FD;&#x4F1A;&#x518D;&#x6B21;&#x6B63;&#x5E38;&#x5B8C;&#x6210;&#x3002;</p>
<p>&#x53EF;&#x4EE5;&#x901A;&#x8FC7;&#x63D0;&#x4F9B; <code>onError</code> &#x9009;&#x9879;&#x6765;&#x8986;&#x76D6; Reactions &#x7684;&#x9ED8;&#x8BA4;&#x65E5;&#x5FD7;&#x884C;&#x4E3A;&#x3002;
&#x793A;&#x4F8B;:</p>
<pre><code class="lang-javascript"><span class="hljs-keyword">const</span> age = observable.box(<span class="hljs-number">10</span>)

<span class="hljs-keyword">const</span> dispose = autorun(() =&gt; {
    <span class="hljs-keyword">if</span> (age.get() &lt; <span class="hljs-number">0</span>)
        <span class="hljs-keyword">throw</span> <span class="hljs-keyword">new</span> <span class="hljs-built_in">Error</span>(<span class="hljs-string">&quot;Age should not be negative&quot;</span>)
    <span class="hljs-built_in">console</span>.log(<span class="hljs-string">&quot;Age&quot;</span>, age.get())
}, {
    onError(e) {
        <span class="hljs-built_in">window</span>.alert(<span class="hljs-string">&quot;Please enter a valid age&quot;</span>)
    }
})
</code></pre>
<p>&#x4E00;&#x4E2A;&#x5168;&#x5C40;&#x7684; onError &#x5904;&#x7406;&#x65B9;&#x6CD5;&#x53EF;&#x4EE5;&#x4F7F;&#x7528; <code>onReactionError(handler)</code> &#x6765;&#x8BBE;&#x7F6E;&#x3002;&#x8FD9;&#x5728;&#x6D4B;&#x8BD5;&#x6216;&#x76D1;&#x63A7;&#x4E2D;&#x5F88;&#x6709;&#x7528;&#x3002;</p>

                                
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